For now, it's tough noogies. The Spiritless DO NOT hang out in the Glade. As their section of the story says, they're scattered all over the place in different worlds.

Also, you have to remember that they're the equivalent of very intelligent/responsive/trainable horses (if you're familiar with Mercedes Lackey's Shin'a'in warhorses, that's basically their capability). The only difference is that, unless they've been bred out to normal horses enough to dilute the power, they can worldwalk - but only by themselves. They cannot carry passengers.

Whether or not your Spiritless' blood is diluted and it has no ability to worldwalk is your choice.

Spiritless can live for up to 40 years.

In light of both their capabilities and limitations, I don't really recommend them as 'main' RP characters, only as sig candy or as a pet/mount for an RP character.